A sushi chef told me it was called "California roll" because CA = Crab + Avocado, so I've been spreading that around... I feel cheated!
Funnily, I am part of the (few?) people that actually prefer imitation crab meat to real crab meat. If only because cracking open crab shells is too troublesome.
You know you can pay other people to do that. Crab meat it also available in a can. Snails too, that always tickles me.
When I eat something someone else has made and I know it came predominantly from cans and jars I'll take something like: "Did you make this?! ... Wow! You sure know how to open a can!".
It's a type of fish cake, basically. It's white fish meat ground into a paste and formed. Surimi is made into things that aren't imitation crab, too! Fish balls and fish cakes and all sorts of things.
What is enough to know about this, that it is blended paste, which means it gradually becomes composed of the cheapest available ingredients as the cost is continually lowered, while the experience kept up using extenders, like bologna for example. This is about this kind of a food you have to know. Happy distressing!